Blind Spot Fuck Up

So, although I fancy myself an excellent driver (and in the company of a few excellent drivers), I have noticed that I'm making a potentially fatal error on a recurring basis.

When changing lanes at speed, I'm missing the vehicle immediately to the right or left. I check the mirrors and give the cursory glance right or left to check the lane the blind spot car, but upon executing, I've noticed -- several times of late -- I've cut cars off. I'm bemused that I'm missing these cars in the sequence.

I replay the situations in my head and, at first, I thought the other cars were just going so fast that they were catching up. But, no. I'm fucking up. Tired or rested. Heavy or moderate traffic. I'm never on the phone. Just fucking up.

I have to fix this or someone's gonna get hurt.